Project planning (CÔNG NGHỆ PHẦN mềm SLIDE)

Project planning Project planning involves breaking down the work into parts and assign these to project team members, anticipate problems that might arise and prepare tentative solutio

Chapter 23 – Project planning

Project planning

 Project planning involves breaking down the work into parts and assign these to project team members,

anticipate problems that might arise and prepare

tentative solutions to those problems

 The project plan, which is created at the start of a

project, is used to communicate how the work will be

done to the project team and customers, and to help

assess progress on the project

Planning stages

 At the proposal stage, when you are bidding for a

contract to develop or provide a software system

 During the project startup phase, when you have to plan who will work on the project, how the project will be

broken down into increments, how resources will be

allocated across your company, etc

 Periodically throughout the project, when you modify

your plan in the light of experience gained and

information from monitoring the progress of the work

Proposal planning

requirements

 The aim of planning at this stage is to provide

information that will be used in setting a price for the

system to customers

 Project pricing involves estimating how much the

software will cost to develop, taking factors such as staff costs, hardware costs, software costs, etc into account

Project startup planning

requirements but do not have design or implementation information

 Create a plan with enough detail to make decisions

about the project budget and staffing

 This plan is the basis for project resource allocation

 The startup plan should also define project monitoring mechanisms

 A startup plan is still needed for agile development to

Development planning

project progresses and you know more about the

software and its development

 The project schedule, cost-estimate and risks have to be regularly revised

Software pricing

Software pricing

 Estimates are made to discover the cost, to the

developer, of producing a software system

 You take into account, hardware, software, travel, training and effort costs.

 There is not a simple relationship between the

development cost and the price charged to the customer

 Broader organisational, economic, political and business considerations influence the price charged

Factors affecting software pricing

Contractual terms A customer may be willing to allow the developer to retain

ownership of the source code and reuse it in other projects The price charged may then be less than if the software source code is handed over to the customer.

Cost estimate

uncertainty If an organization is unsure of its cost estimate, it may increase its price by a contingency over and above its

normal profit.

Financial health Developers in financial difficulty may lower their price to

gain a contract It is better to make a smaller than normal profit or break even than to go out of business Cash flow is more important than profit in difficult economic times.

Factors affecting software pricing

Market opportunity A development organization may quote a low price

because it wishes to move into a new segment of the software market Accepting a low profit on one project may give the organization the opportunity to make a greater profit later The experience gained may also help it develop new products.

Requirements volatility If the requirements are likely to change, an organization

may lower its price to win a contract After the contract is awarded, high prices can be charged for changes to the requirements.

Pricing to win

 The software is priced according to what the software

developer believes the buyer is willing to pay

 If this is less that the development costs, the software functionality may be reduced accordingly with a view to extra functionality being added in a later release

change and these may be priced at a higher level to

make up the shortfall in the original price

Plan-driven development

Plan-driven development

to software engineering where the development process

is planned in detail

 Plan-driven development is based on engineering project

management techniques and is the ‘traditional’ way of

managing large software development projects

 A project plan is created that records the work to be

done, who will do it, the development schedule and the work products

 Managers use the plan to support project decision

Plan-driven development – pros and cons

that early planning allows organizational issues

(availability of staff, other projects, etc.) to be closely

taken into account, and that potential problems and

dependencies are discovered before the project starts, rather than once the project is underway

is that many early decisions have to be revised because

of changes to the environment in which the software is to

be developed and used

Project plan supplements

Configuration management plan Describes the configuration management procedures

and structures to be used

Deployment plan Describes how the software and associated hardware

(if required) will be deployed in the customer’s environment This should include a plan for migrating data from existing systems

Maintenance plan Predicts the maintenance requirements, costs, and

effort

Quality plan Describes the quality procedures and standards that

will be used in a project

Validation plan Describes the approach, resources, and schedule used

for system validation

The planning process

 Project planning is an iterative process that starts when you create an initial project plan during the project

startup phase

 Plan changes are inevitable

 As more information about the system and the project team

becomes available during the project, you should regularly

revise the plan to reflect requirements, schedule and risk

changes.

 Changing business goals also leads to changes in project plans

As business goals change, this could affect all projects, which may then have to be re-planned

The project planning process

Planning assumptions

 You should make realistic rather than optimistic

assumptions when you are defining a project plan

project, and these lead to project delays

 Your initial assumptions and scheduling should therefore take unexpected problems into account

 You should include contingency in your plan so that if

things go wrong, then your delivery schedule is not

seriously disrupted

Risk mitigation

 If there are serious problems with the development work that are likely to lead to significant delays, you need to initiate risk mitigation actions to reduce the risks of

project failure

 In conjunction with these actions, you also have to

re-plan the project

 This may involve renegotiating the project constraints

and deliverables with the customer A new schedule of when work should be completed also has to be

established and agreed with the customer

Project scheduling

Project scheduling

 Project scheduling is the process of deciding how the

work in a project will be organized as separate tasks,

and when and how these tasks will be executed

task, the effort required and who will work on the tasks that have been identified

complete each task, such as the disk space required on

a server, the time required on specialized hardware,

such as a simulator, and what the travel budget will be

Project scheduling activities

 Split project into tasks and estimate time and resources required to complete each task

use of workforce

caused by one task waiting for another to complete

experience

The project scheduling process

Scheduling problems

 Estimating the difficulty of problems and hence the cost

of developing a solution is hard

 Productivity is not proportional to the number of people working on a task

 Adding people to a late project makes it later because of communication overheads

contingency in planning

Schedule presentation

 Graphical notations are normally used to illustrate the

project schedule

should not be too small They should take about a week

or two

 Bar charts are the most commonly used representation for

project schedules They show the schedule as activities or

resources against time.

 Activity networks

Project activites

 Project activities (tasks) are the basic planning element Each activity has:

 a duration in calendar days or months,

 an effort estimate, which shows the number of person-days or person-months to complete the work,

 a deadline by which the activity should be complete,

 a defined end-point, which might be a document, the holding of

a review meeting, the successful execution of all tests, etc.

Milestones and deliverables

 Milestones are points in the schedule against which you can assess progress, for example, the handover of the system for testing

 Deliverables are work products that are delivered to the customer, e.g a requirements document for the system

Tasks, durations, and dependencies

Task Effort

(person-days) Duration (days) Dependencies

Activity bar chart

Staff allocation chart

Agile planning

Agile planning

 Agile methods of software development are iterative

approaches where the software is developed and

delivered to customers in increments

 Unlike plan-driven approaches, the functionality of these increments is not planned in advance but is decided

during the development

 The decision on what to include in an increment depends on

progress and on the customer’s priorities

 The customer’s priorities and requirements change so it makes sense to have a flexible plan that can

Agile planning stages

and decides on the features that should be included in a release of a system

 Iteration planning, which has a shorter term outlook, and focuses on planning the next increment of a system This

is typically 2-4 weeks of work for the team

Approaches to agile planning

 Covered in Chapter 3

done) with daily reviews of progress and problems

 Developed originally as part of Extreme Programming (XP)

 Dependent on user stories as a measure of progress in the

project

Story-based planning

 The planning game is based on user stories that reflect the features that should be included in the system

 The project team read and discuss the stories and rank them in

order of the amount of time they think it will take to implement the story

 Stories are assigned ‘effort points’ reflecting their size and difficulty

of implementation

 The number of effort points implemented per day is measured giving

an estimate of the team’s ‘velocity’

 This allows the total effort required to implement the system to be estimated

The planning game

Release and iteration planning

 Release planning involves selecting and refining the

stories that will reflect the features to be implemented in

a release of a system and the order in which the stories should be implemented

 Stories to be implemented in each iteration are chosen, with the number of stories reflecting the time to deliver

an iteration (usually 2 or 3 weeks)

 The team’s velocity is used to guide the choice of stories

so that they can be delivered within an iteration

Task allocation

 During the task planning stage, the developers break

down stories into development tasks

 A development task should take 4–16 hours

 All of the tasks that must be completed to implement all of the stories in that iteration are listed

 The individual developers then sign up for the specific tasks that they will implement

 Benefits of this approach:

 The whole team gets an overview of the tasks to be completed

in an iteration

 The delivery schedule is never extended

Agile planning difficulties

 Agile planning is reliant on customer involvement and

availability

 This can be difficult to arrange, as customer

representatives sometimes have to prioritize other work and are not available for the planning game

traditional project plans and may find it difficult to engage

in an agile planning process

Agile planning applicability

 Agile planning works well with small, stable development teams that can get together and discuss the stories to be implemented

distributed, or when team membership changes

frequently, it is practically impossible for everyone to be involved in the collaborative planning that is essential for agile project management

Estimation techniques

Estimation techniques

 Organizations need to make software effort and cost

estimates There are two types of technique that can be used to do this:

 Experience-based techniques The estimate of future effort

requirements is based on the manager’s experience of past

projects and the application domain Essentially, the manager makes an informed judgment of what the effort requirements are likely to be.

 Algorithmic cost modeling In this approach, a formulaic approach

is used to compute the project effort based on estimates of

product attributes, such as size, and process characteristics,

such as experience of staff involved.

Estimate uncertainty

Experience-based approaches

on experience of past projects and the effort expended in these projects on software development activities

 Typically, you identify the deliverables to be produced in

a project and the different software components or

systems that are to be developed

individually and compute the total effort required

 It usually helps to get a group of people involved in the effort estimation and to ask each member of the group to

Problem with experience-based approaches

 The difficulty with experience-based techniques is that a new software project may not have much in common

with previous projects

project will often use unfamiliar techniques such as web services, application system configuration or HTML5

 If you have not worked with these techniques, your

previous experience may not help you to estimate the effort required, making it more difficult to produce

accurate costs and schedule estimates

Algorithmic cost modelling

 Cost is estimated as a mathematical function of

product, project and process attributes whose

values are estimated by project managers:

 Effort = A   Size B  M

 A is an organisation-dependent constant, B reflects the disproportionate effort for large projects and M is a multiplier reflecting product, process and people attributes.

estimation is code size

 Most models are similar but they use different values for

A, B and M

Estimation accuracy

accurately when it is finished

 Several factors influence the final size

 Use of reused systems and components;

 Programming language;

 Distribution of system.

estimate becomes more accurate

 The estimates of the factors contributing to B and M are subjective and vary according to the judgment of the

Effectiveness of algorithmic models

estimate the effort required to develop a system

However, these models are complex and difficult to use

uncertainty in estimating their values

 This complexity means that the practical application of algorithmic cost modeling has been limited to a relatively small number of large companies, mostly working in

defense and aerospace systems engineering